Policy options to achieve the 80% cut Land Management, Sequestration and Sinks Robin Matthews Climate Change Theme Leader Macaulay Institute Aberdeen AB15 8QH Presentation at Scottish Parliament, November 19, 2008

Structure of the talk Background Contribution to overall Scottish GHG emissions made by the land use sector Trends in GHG emissions from the land use sector Scope for the use of land for sequestration and sinks

Emissions from the land use sector N2O: N-fertiliser, wet acid soils, animals CH4: livestock, natural peat bogs CO2: cultivation, fuel consumption However, Scotland’s soils contain: Shallow organic soils: ~1400 Mt C Peat soils: 2000-4500 Mt C Forests and soils have considerable capacity to store carbon

Carbon sequestration

Effect of land use change on soil C Geescroft Wilderness: converted from arable to woodland in 1880s New Zealand -1.15 t C ha-1 y-1 in first 3 years average 0.33 t C ha-1 y-1

Scale of the contribution 62% of UK’s removals is by Scottish forests (2003) Scotland’s total emissions: 59 Mt CO2e yr-1 Land use emissions: 11.8 Mt CO2e yr-1 From ‘Changing Our Ways: Scotland’s Climate Change Programme’, SEERAD, 2006.

Trends in main GHG source/sinks Forestry Livestock Land use change N fertiliser application

LULUCF source/sink trends Scotland decline in cattle and sheep numbers 60% reduction increase in sink size by 78% From AEA (2008), Greenhouse Gas Inventories for England, Scotland, Wales & Northern Ireland: 1990 - 2006

Agricultural management alternative ‘carbon-neutral’ energy crops increased C sequestration through different ground covers and land management reducing CH4 emissions from livestock more efficient use of organic and inorganic fertilisers Initial calculations suggest abatement potential of 1.57 MtCO2e

Land use change: arable to grassland Scotland: 600,250 ha

Land use change: arable to grassland Abatement potential Ignoring land suitability for the moment 600,250 ha of cropland in Scotland Assume all is converted into grassland Sequestration rate: ~1.5 t CO2 ha-1 y-1 Abatement potentials: setaside: 0.97 MtCO2e y-1 beef: 0.11 MtCO2e y-1 sheep: 0.40 MtCO2e y-1 dairy: -8.12 MtCO2e y-1

Land use change: forestry Options afforestation of abandoned agricultural lands forest management to increase carbon density at the stand/landscape level maintaining forest cover minimising soil C loss increasing rotation lengths increasing growth managing drainage increasing off-site carbon stocks in wood products enhancing product and fuel substitution

Land use change: forestry Forestry Strategy: Increase of forestry from 17-25% Current forest area: 1,347,001 ha 2050 target: 1,969,300 ha (+622,299 ha) Assume sequestration rate is 11 t CO2 ha-1 yr-1 Abatement potential: 6.8 Mt CO2e yr-1 (12.5%) ‘Changing Our Ways’ (2006): The forestry sector should deliver annual carbon savings of 2.2 Mt CO2e by 2010 (4.0%) 2.9 Mt CO2e by 2015 (5.4%) 3.7 Mt CO2e by 2020 (6.7%)

Forest planting rates

Tradeoffs for landuse As climates warm, more marginal areas will become suitable for agriculture What will be the implications for: food production bioenergy timber water quality, quantity soils carbon storage biodiversity

Land use change: peat restoration total peat area: 1,096,000 ha degraded basin peat: ~24,000 ha eroded blanket peat: ~9,000 ha functioning peat-bog sequesters ~730 kg CO2 ha-1 y-1 degraded bog could lose ~730 kg CO2 ha-1 y-1 one-off cost of £400-1000 per ha abatement potential: 1460 × 33,000 × 10-9 = 0.048 Mt CO2e y-1 0.09% of Scotland’s emissions of 55 Mt CO2 yr-1

Summary Abatement potential Fraction of AFOLU Fraction of total (MtCO2e yr-1) (%) Agriculture 1.57 13.3 2.7 Cropland to grassland 0.97 8.2 1.6 Forestry 6.80 57.6 11.5 Peatland 0.05 0.4 0.1 TOTAL 9.39 79.5 15.9 Proviso: Very ‘ballpark’ figures – indicative only! Many assumptions that need to be tested More detailed UK study to be published by Office of Climate Change in December

Marginal abatement cost curves Cheap option, big emission savings Expensive options, small emission savings Financial savings Options ranked in decreasing order of cost-effectiveness Width of each bar (x-axis): abatement potential (AP) Height of each bar (y-axis): cost-effectiveness (CE) Comparing the abatement scenario with a baseline Now I’d like to move on to methodology. To find out the most effective way of reducing greenhouse gas emissions from agriculture, the marginal abatement cost curve analysis was used. This illustrative MAC curve shows various options to reduce GHG emissions, ranked in decreasing order of cost-effectiveness along the x-axis. On the MAC curve, the width of each bar indicates the volume of the emission savings, in other words the abatement potential, while the height of each bar shows the cost-effectiveness of the measure, which is calculated by dividing the total cost of the measure by the abatement potential. Measures below the x-axis indicate savings, while measures above the x-axis illustrate costs For example, this wide and flat bar indicates an option which is cheap, and at the same time generates huge emission savings. On the other hand, these tall and narrow bars on the right represent expensive options with low abatement potentials.